Effects of different plant hormones or PEG seed soaking on maize resistance to drought stress

Drought stress has a major impact on plant growth and productivity, and seed soaking is an important way to increase seedling resistance to drought stress. This study investigated whether drought hardening chemicals, such as polyethylene glycol (PEG), or plant growth regulators enhance plant drought tolerance. The effects of PEG and several plant hormones, such as indoleacetic acid, gibberellic acid 3, 6-benzylaminopurine (6-BA), on seed germination and seedling growth under drought stress were analyzed. The results revealed that seed soaking with 5 x 10(-3) mg L-1 6-BA or 10% PEG improved maize seed germination parameters under drought stress, including seedlings dry weight, seed vigor and germination rate. In addition, some physiological indices, such as superoxide dismutase and catalase activities, soluble protein contents and malondialdehyde etc. in seedlings under drought stress were improved compared with the control. Therefore, the application of 6-BA or PEG as a seed soak treatment had a significant and synergistic effect on seed germination and seedling growth under drought stress. However, the PEG seed soak treatment maybe slightly lead to plant damage and then improved plant ability to acquire some resistance to stress, the 6-BA were not so.